1. Field of the Invention
This invention relates to the field of minimally invasive surgery (MIS). More specifically, it relates to a method of performing MIS by projecting images of internal organs, tissues, and surgical tools externally on the skin of a patient to create a virtual effect that the skin is transparent.
2. Description of the Prior Art
MIS utilizes small incisions in the body for the placement and manipulation of surgical equipment. MIS has been widely adapted and performed as an alternative to open surgery because it minimizes trauma, shortens hospitalizations, and increases recovery time. In 2009, the global market for MIS equipment was roughly US$15 billion with nearly US$1.7 billion spent specifically on endoscopic cameras and monitoring systems.
While MIS provides many benefits, it often takes longer to complete than equivalent open surgeries. In particular, MIS is hindered by limited viewpoints and insertion points, inconsistent and unclear orientation of video, and limited touch sensing and hand motion due to long-stick surgical tools. As a result, MIS requires significantly more training than regular open surgery, which prevents or discourages many surgeons to master the skills for MIS, especially in remote and developing regions or less-than-ideal surgical venues.
Several techniques have been developed to overcome these limitations. For example, the da Vinci® Integrated Surgical Robotic System is a high-end minimally invasive surgery robot. Hand and wrist motions of a surgeon are mapped to a robot hand motion at the da Vinci® system, and an image from an endoscope at the patient terminal is displayed on a surgeon's console. With two cameras integrated in one endoscope, the surgeons can see some level of stereo. The major benefit of the da Vinci® system is the hand-eye coordination presents the MIS as an open surgery from the surgeon's point of view.
The da Vinci® system, however, is very expensive and requires multiple incisions for the robotic arms to perform the operation. Moreover, the da Vinci® system has unwieldy robotics arms that limit its application; for example, the robotics arms are too big to insert tools near one another and have conflicts with other surgical tools during procedures.
In both traditional MIS and robotic aided MIS, the image displayed to the surgeons is via endoscopes. The state of the art commercial videoscopes (i.e. laparoscopes, endoscopes) for MIS have, and are encumbered by, cabling for power, video, and a xenon light source inside a semi-flexible or rigid mechanical rod. Many surgeons have expressed their disappointment with the fundamental limitations of these scopes based on their experience with hundreds of MIS operations. Though quite good in image quality, these videoscopes are cumbersome and require a point of access into the patient, either through a separate incision or through a separate trocar site in a multitrocar access port. The videoscope cables for light, video image, and power clutter and consume space in the operative field. They also require supporting manpower in the operating room to hold the scope and redirect it as indicated to maintain consistent and stable views of the operation being undertaken. Some developing approaches to intracavity visualization bypass the rod-lens approach of conventional videoscopes but the resulting video platforms still maintain a significant spatial presence within the operating cavity and require points of access (e.g. incisions and/or trocars) to link power and video images. In addition, the limitation of the viewpoint and view angle of the rigid endoscope is a handicap for surgeons. The misinterpretation of the image orientation on an overhead monitor also poses a significant problem to the hand-eye coordination for the surgeons and requires great skills and train to master and compensate.
Various approaches for visualization in image-guided interventions have been proposed to achieve “seeing through” effect by applying the concept of augmented reality. Augmented reality enables the surgeons to focus on the surgical site without dividing his or her attention between the patient and a separate monitor and provides hand-eye coordination as the surgeon observes the operation room. A CT image of a patient overlayed with the patient and appearing at the location of the actual anatomy is an example of augmented reality. Usually the location of the surgery tool is tracked and graphically drawn as a virtual tool and displays on the CT or other images based on the tracking to guide surgeons to operate. If the mapping does not align correctly with the patient and the surgical tool, the visualization can be dangerous. It is very challenging to achieve satisfactory accurate alignment between the tracking data and the image since it requires precise models of the patient and models of instruments.
What is needed is a method of performing MIS by projecting images of internal organs and tissues externally on the skin of a patient to create a virtual effect that the skin is transparent. Such a method would not encounter the difficult instrument mapping and alignment problem of the prior art because it captures the surgical anatomy and the surgical instrument at the same time and in the same frame.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the art how the limitations of the art could be overcome.